Nuclear power best to fight climate change

In the battle against climate change, one of the best-kept secrets is the small modular reactor.

The U.S. fleet of about 100 nuclear power plants consists of large reactors of 1,200 megawatts or more. These plants produce more than 60 percent of the nation’s carbon-free electricity, far more than solar and wind energy combined, and reactors like those at the Calvert Cliffs plant in Maryland supply power around the clock, day after day, regardless of weather conditions.

According to the Energy Information Administration, last year U.S. nuclear plants on average produced electricity 91.9 percent of the time. And during the past three years, the Calvert Cliffs units produced electricity at 93.7 percent of full capacity, among the highest capacity factors for a nuclear plant in this country.

James Hansen, one of the world’s leading atmospheric scientists who headed NASA’s Goddard Research Institute for many years, maintains that a global expansion of nuclear power offers the best chance of preventing the worst effects of climate change. Hansen, who has solid environmental credentials, estimates nuclear power has already saved more than 2 million lives globally that would have been lost to air pollution from burning fossil fuels.

Although nuclear-generated electricity is reliable and emission-free, few utilities these days can afford to build large nuclear plants. As a result, small modular reactors – roughly the size of those that power nuclear submarines and aircraft carriers – have become the preferred option.

Ranging from 50 megawatts to 300 megawatts, these reactors are less than one-third the size of conventional nuclear plants and cost much less to build. SMRs are designed to be constructed in factories in order to improve quality control and reduce costs, then shipped by barge, truck or railroad for assembly at a nuclear site.

What’s really new and different about SMRs is that some can be assembled in clusters of up to 12 modules, each operating independently of the others, so if one is taken offline for refueling or maintenance, the others can continue to generate electricity. New modules can be added as the need for additional electricity arises.

Approximately 50 nuclear companies are developing designs for SMRs. Some of the reactors use liquid metal or gas instead of water for cooling purposes. They include reactors with molten salt, which acts as both a coolant and a medium for the fuel, and a so-called pebble-bed reactor, in which the uranium fuel is contained in both ceramic and graphite-covered balls.

NuScale, an Oregon-based firm, is typical of many of the SMR companies. NuScale is working on a design for a 50-megawatt SMR, the core of which will be cooled by natural circulation, requiring fewer components such as pipes and valves and safety systems than a conventional reactor.

By the end of this year, the company expects to apply to the Nuclear Regulatory Commission for certification of the SMR design. Construction of the SMR is scheduled to take 36 months.

The Department of Energy forecasts an 18 percent growth in electricity demand by 2040. To maintain the benefits of a balanced mix of clean energy sources, the United States will need more than 100,000 megawatts of new nuclear-generating capacity by mid-century.

SMRs, which are expected to be deployed by the early 2020s, are ideally suited to help meet that need.

Dan Ervin is a professor of finance at the Perdue School of Business at Salisbury University.